Measurement system and measurement method

ABSTRACT

A measurement system according to an aspect of the present invention enables measurement of an intensity distribution of diffracted X-rays obtained by irradiating a fillet portion of a metallic structure with X-rays, the metallic structure comprising: an axis portion; and a flange portion protruding radially from the axis portion, wherein the metallic structure comprises the fillet portion in a connection portion between the axis portion and the flange portion, the measurement system including: a diffracted X-rays measurement device provided with an irradiation unit that irradiates the fillet portion with X-rays; and a positioning device that positions the diffracted X-rays measurement device with respect to the fillet portion, in which the positioning device including: a moving mechanism that moves three-dimensionally the diffracted X-rays measurement device relative to the fillet portion; and a rotation mechanism that rotates the diffracted X-rays measurement device in such a direction that an angle of incidence of the X-rays with respect to the fillet portion is changed.

TECHNICAL FIELD

The present invention relates to a measurement system and a measurementmethod.

BACKGROUND ART

Recently, a technique for measuring a residual stress using X-rays hasbeen widely applied. In this technique, a lattice distortion occurringinside a specimen having a crystalline structure is measured usingX-rays, and the measurement result is converted into a residual stress.

As a method for measuring a residual stress using X-rays, a cos α methodis known. The cos α method includes: irradiating a specimen with X-raysat a specific angle of incidence; two-dimensionally detectingintensities of diffracted X-rays generated by reflection of the X-raysby the specimen; and measuring a residual stress based on a diffractionring formed by an intensity distribution of the diffracted X-rays asdetected.

Today, determining hardness and the like of a specimen throughcalculation of a half width of an X-ray diffraction intensity curvebased on an intensity distribution of the diffracted X-rays is alsopracticed.

An X-ray stress measuring apparatus in which an X-ray emitter that emitsX-rays, an imaging plate on which a diffraction ring due to diffractedX-rays is formed, and the like are disposed in a single housing (seeJapanese Unexamined Patent Application, Publication No. 2012-225796) canbe used as an X-ray stress measuring apparatus for measuring a residualstress of a fillet portion in a metal structure including: an axisportion having a cylindrical shape; and a flange portion (plate-shapedportion) protruding radially from the axis portion, wherein the filletportion for alleviating stress concentration is provided in a connectionportion between the axis portion and the flange portion.

PRIOR ART DOCUMENTS Patent Documents

-   Patent Document 1: Japanese Unexamined Patent Application,    Publication No. 2012-225796

SUMMARY OF THE INVENTION Problems to be Solved by the Invention

In the measurement of the residual stress by the cos α method, the angleof incidence is typically set to be greater than or equal to 15° andless than or equal to 65°. However, with regard to a metal structureincluding: an axis portion having a cylindrical shape; and a flangeportion (plate-shaped portion) protruding radially from the axisportion, wherein a fillet portion for alleviating stress concentrationis provided in a connection portion between the axis portion and theflange portion, for example in a case of irradiating a plurality ofpositions in the fillet portion with X-rays, there is a higher risk ofinterference between the flange portion or the axis portion and theX-ray stress measuring apparatus, leading to difficulty in arranging theX-ray stress measuring apparatus in a desired position.

The present invention was made in view of the foregoing circumstances,and an object of the present invention is to provide a measurementsystem and a measurement method that enable easy measurement of anintensity distribution of diffracted X-rays in a desired arrangement.

Means for Solving the Problems

A measurement system according to an aspect of the present inventionenables measurement of an intensity distribution of diffracted X-raysobtained by irradiating a fillet portion of a metallic structure withX-rays, the metallic structure comprising: an axis portion; and a flangeportion protruding radially from the axis portion, wherein the metallicstructure comprises the fillet portion in a connection portion betweenthe axis portion and the flange portion, the measurement systemincluding: a diffracted X-rays measurement device provided with anirradiation unit that irradiates the fillet portion with X-rays; and apositioning device that positions the diffracted X-rays measurementdevice with respect to the fillet portion, in which the positioningdevice includes: a moving mechanism that moves three-dimensionally thediffracted X-rays measurement device relative to the fillet portion; anda rotation mechanism that rotates the diffracted X-rays measurementdevice in such a direction that an angle of incidence of the X-rays withrespect to the fillet portion is changed.

The measurement system includes a positioning device that positions thediffracted X-rays measurement device with respect to the fillet portion,in which the positioning device includes: a moving mechanism that movesthree-dimensionally the diffracted X-rays measurement device relative tothe fillet portion; and a rotation mechanism that rotates the diffractedX-rays measurement device in such a direction that an angle of incidenceof the X-rays with respect to the fillet portion is changed, whereby anintensity distribution of diffracted X-rays obtained by irradiating thefillet portion with X-rays can be easily measured in a desiredarrangement.

It is preferred that the measurement system further includes a controlunit that controls movement by the moving mechanism and rotation by therotation mechanism such that the diffracted X-rays measurement devicedoes not come into contact with the axis portion and the flange portion.The measurement system can measure the intensity distribution of thediffracted X-rays more easily in a desired arrangement due to furthercomprising a control unit that controls movement by the moving mechanismand rotation by the rotation mechanism such that the diffracted X-raysmeasurement device does not come in contact with the axis portion andthe flange portion.

It is preferred that the control unit controls the movement by themoving mechanism and the rotation by the rotation mechanism within sucha range that the diffracted X-rays measurement device can detect a peakof diffracted X-rays. Due to the control unit thus controlling themovement by the moving mechanism and the rotation by the rotationmechanism within such a range that the diffracted X-rays measurementdevice can detect a peak of diffracted X-rays, the intensitydistribution of the diffracted X-rays can be measured easily andreliably.

In a case in which: an axis passing through a fillet center and beingparallel to a central axis of the axis portion is represented by anX-axis; an axis passing through the fillet center and being parallel toa protrusion direction of the flange portion is represented by a Z-axis;a coordinate of the fillet center is represented by (0, 0); a coordinateof a rotation center of the diffracted X-rays measurement device isrepresented by (X, Z); an irradiation distance of the X-rays by thediffracted X-rays measurement device is denoted by L [mm]; a minimumvalue of the irradiation distance of the X-rays is denoted by L_(min)[mm]; a maximum value of the irradiation distance of the X-rays isdenoted by L_(max) [mm]; a fillet angle is denoted by θ [°]; a filletradius is denoted by R [mm]; an angle of incidence of the X-rays isdenoted by Ψ[°]; a distance between an end portion of a housing of thediffracted X-rays measurement device on the fillet portion side and therotation center in the irradiation direction of the X-rays is denoted byh [mm]; a top-to-bottom width of an end portion of the housing on a sideadjacent to the fillet portion is denoted by W [mm]; a complementaryangle of the Bragg angle is denoted by η [°]; a top-to-bottom width of adetection region of a two-dimensional detector of the diffracted X-raysmeasurement device is denoted by D [mm], and an interval between theflange portion and an imaginary straight line which passes through thefillet center and is parallel to the flange portion is denoted by a[mm], it is preferred that the following inequality 1 and inequality 2are satisfied:

(L _(min) h)sin(θ+Ψ)−R sin θ≤X≤(L _(max) +h)sin(θ+Ψ)−R sin θ  1

(L _(min) +h)cos(θ+Ψ)−R cos θ≤Z≤(L _(max) +h)cos(θ+Ψ)−R cos θ  2

wherein with respect to an imaginary straight line which passes througha measurement site and the fillet center, the angle of incidence Ψ ofthe X-rays is defined to be positive in a case of tilting toward theaxis portion, and is defined to be negative in a case of tilting towardthe flange portion: in a case in which Ψ≥0, the irradiation distance Lof the X-rays satisfies the following inequality 3; and in a case inwhich Ψ<0, the irradiation distance L of the X-rays satisfies thefollowing inequality 4:

$\begin{matrix}{\frac{{- {R\left( {1 - {\cos\theta}} \right)}} + {\frac{W}{2}{\sin\left( {\theta + \Psi} \right)}}}{\cos\left( {\theta + \Psi} \right)} \leqq L \leqq \frac{D}{2\tan\eta}} & 3\end{matrix}$ $\begin{matrix}{\frac{{R\sin\theta} + {\frac{W}{2}{\cos\left( {\theta + \Psi} \right)}} - a}{\sin\left( {\theta + \Psi} \right)} \leqq L \leqq \frac{D}{2\tan\eta}} & 4\end{matrix}$

Due to positioning the diffracted X-rays measurement device within arange that satisfies the above inequalities 1 and 2, the measurementsystem can easily inhibit contact of the axis portion and the flangeportion with the diffracted X-rays measurement device.

It is preferred that the control unit controls the movement by themoving mechanism and the rotation by the rotation mechanism on basis ofthe following inequality 5 in a case in which Ψ≥0, and controls themovement by the moving mechanism and the rotation by the rotationmechanism on basis of the following inequality 6 in a case in which Ψ<0,

$\begin{matrix}{Z \geqq {{- R} + {h{\cos\left( {\theta + \Psi} \right)}} + {\frac{W}{2}{\sin\left( {\theta + \Psi} \right)}}}} & 5\end{matrix}$ $\begin{matrix}{X \geqq {{- a} + {h{\sin\left( {\theta + \Psi} \right)}} + {\frac{W}{2}{\cos\left( {\theta + \Psi} \right)}}}} & 6\end{matrix}$

Due to the control unit thus controlling the movement by the movingmechanism and the rotation by the rotation mechanism on the basis of theabove inequalities 5 and 6, the intensity distribution of the diffractedX-rays can be measured easily and reliably, while contact of the axisportion and the flange portion with the diffracted X-rays measurementdevice is inhibited.

It is preferred that the moving mechanism includes: a first moving bodythat fits to an outer peripheral face of the axial portion and rotatesin a circumferential direction relative to the axial portion; aperpendicular axis that is connected to the first moving body andextends in a direction orthogonal to the central axis of the axisportion; a second moving body that is connected to the perpendicularaxis and movable in an axial direction of the perpendicular axis; and aslide mechanism that moves the first moving body or the perpendicularaxis in an axial direction of the axis portion, in which the diffractedX-rays measurement device is connected to the second moving body. Due tothe moving mechanism thus including: a first moving body that fits to anouter peripheral face of the axial portion and rotates in acircumferential direction relative to the axial portion; a perpendicularaxis that is connected to the first moving body and extends in adirection orthogonal to the central axis of the axis portion; a secondmoving body that is connected to the perpendicular axis and movable inan axial direction of the perpendicular axis; and a slide mechanism thatmoves the first moving body or the perpendicular axis in an axialdirection of the axis portion, in which the diffracted X-raysmeasurement device is connected to the second moving, the intensitydistribution of the diffracted X-rays can be more easily measured in adesired arrangement.

It is preferred that the diffracted X-rays measurement device isconfigured to be able to calculate a residual stress of the filletportion by the cos α method. The measurement system being able to easilymeasure the intensity distribution of the diffracted X-rays in a desiredarrangement is suitable for calculating the residual stress of thefillet portion.

It is preferred that the diffracted X-rays measurement device isconfigured to be able to calculate a half width of an X-ray diffractionintensity curve. The measurement system being able to easily measure theintensity distribution of the diffracted X-rays in a desired arrangementis suitable for calculating the half width of the X-ray diffractionintensity curve.

A measurement method according to another aspect of the presentinvention enables measurement of an intensity distribution of diffractedX-rays obtained by irradiating a fillet portion of a metallic structurewith X-rays, the metallic structure comprising: an axis portion; and aflange portion protruding radially from the axis portion, wherein themetallic structure comprises the fillet portion in a connection portionbetween the axis portion and the flange portion, the measurement methodusing a diffracted X-rays measurement device provided with anirradiation unit that irradiates the fillet portion with X-rays, andincluding: moving three-dimensionally the diffracted X-rays measurementdevice relative to the fillet portion; rotating the diffracted X-raysmeasurement device in such a direction that an angle of incidence of theX-rays with respect to the fillet portion is changed; and measuring theintensity distribution of diffracted X-rays by the diffracted X-raysmeasurement device.

Due to the measurement method including moving three-dimensionally thediffracted X-rays measurement device relative to the fillet portion; androtating the diffracted X-rays measurement device in such a directionthat an angle of incidence of the X-rays with respect to the filletportion is changed, an intensity distribution of diffracted X-raysobtained by irradiating the fillet portion with X-rays can be easilymeasured in a desired arrangement.

It is preferred that, in the measurement, the residual stress of thefillet portion is calculated by the cos α method. The measurement methodbeing able to easily measure the intensity distribution of thediffracted X-rays in a desired arrangement is suitable for calculatingthe residual stress of the fillet portion.

It is preferred that, in the measurement, a half width of an X-raydiffraction intensity curve is calculated. The measurement method beingable to easily measure the intensity distribution of the diffractedX-rays in a desired arrangement is suitable for calculating the halfwidth of the X-ray diffraction intensity curve.

It is preferred that: the fillet portion is continuously irradiated withX-rays in parallel with at least one of the moving and the rotating; andin the measurement, a single diffraction ring, which is given byoverlapping a plurality of diffraction rings generated by diffraction ofthe X-rays, is determined. Due to the fillet portion thus beingcontinuously irradiated with X-rays in parallel with at least one of themoving and the rotating, and a single diffraction ring, which is givenby overlapping a plurality of diffraction rings generated by diffractionof the X-rays, being obtained in the measurement, easy and highlyaccurate calculation of the residual stress or the half width isenabled.

It is preferred that the measurement method includes, after themeasuring, repeating: at least one of the moving and the rotating; andthe measuring. Due to thus including, after the measuring, repeating: atleast one of the moving and the rotating; and the measuring, moreaccurate calculation of the residual stress or the half width isenabled.

It is preferred that the measurement method further includes determiningan average value of a plurality of calculated values obtained by themeasuring. Due to thus further including determining an average value ofa plurality of calculated values obtained by the measuring, easy andhighly accurate measurement of the residual stress or the half width isenabled.

It is to be noted that according to the present invention, the “filletcenter” as referred to herein means a center of curvature of the filletportion. The “fillet angle” as referred to herein means an angle in aside view, formed between an imaginary straight line which passesthrough the fillet center and is orthogonal to the axis portion, and animaginary straight line which passes through the measurement site andthe fillet center (see θ in FIG. 2 ). The “fillet radius” as referred toherein means a radius of curvature of the fillet portion. The“top-to-bottom width” as referred to herein means a width between asurface being on a side adjacent to the axis portion, and a surfaceopposed to this surface and being on a side adjacent to the flangeportion. The “interval between the flange portion and the imaginarystraight line which passes through the fillet center and is parallel tothe flange portion” as referred to herein means an average value ofintervals at 5 arbitrary points between the imaginary straight line andthe flange portion (excluding the fillet portion).

Effects of the Invention

As described above, the measurement system according to an aspect of thepresent invention and the measurement method according to another aspectof the present invention enable easy measurement of the intensitydistribution of the diffracted X-rays in a desired arrangement.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic perspective view illustrating a state of themeasurement system according to an embodiment of the present inventionin use.

FIG. 2 is a schematic side view illustrating a state in which theresidual stress of the fillet portion is measured by a diffracted X-raysmeasurement device of the measurement system in FIG. 1 .

FIG. 3 is a schematic cross-sectional view taken along A-A line,illustrating the major portion of the moving mechanism of themeasurement system in FIG. 1 .

FIG. 4 is a graph showing a relationship between the angle of incidenceΨ of the X-rays and the measurement error in the residual stress.

FIG. 5 is a graph showing a relationship between the irradiation area ofthe X-rays and the measurement error in the residual stress.

FIG. 6 is a schematic side view illustrating a state of the measurementsystem according to an embodiment different from the measurement systemin FIG. 1 in use.

FIG. 7 is a graph showing a measured result of the residual stress usingthe measurement system in FIG. 1 .

FIG. 8 is a graph showing a relationship between the number of measuredpoints and the measurement time in Example and Comparative Example.

FIG. 9 is a graph showing the half width calculated from the X-raydiffraction intensity curve obtained in the arrangement derived by themeasurement in FIG. 7 .

DESCRIPTION OF EMBODIMENTS

Hereinafter, embodiments of the present invention are described indetail with reference to the drawings.

Measurement System

As illustrated in FIGS. 1 and 2 , a measurement system 1 measures anintensity distribution of diffracted X-rays obtained by irradiating withX-rays a fillet portion 4 of a metallic structure M, the metallicstructure M including: an axis portion 2; and a flange portion 3protruding radially from the axis portion 2, in which the metallicstructure M includes the fillet portion 4 in a connection portionbetween the axis portion 2 and the flange portion 3. The flange portion3 protrudes in a direction perpendicular to a central axis of the axisportion 2. As illustrated in FIG. 2 , the measurement system 1 includesa diffracted X-rays measurement device 10 provided with an irradiationunit 11 that irradiates the fillet portion 4 with X-rays. The diffractedX-rays measurement device 10 is exemplified by an X-ray stress measuringapparatus. In addition, as shown in FIG. 1 and FIG. 3 , the measurementsystem 1 includes a positioning device 20 that positions the diffractedX-rays measurement device 10 with respect to the fillet portion 4.Furthermore, as shown in FIG. 1 and FIG. 3 , the measurement system 1includes a control unit 30 that controls operation of the diffractedX-rays measurement device 10 by the positioning device 20 such that thediffracted X-rays measurement device 10 does not come into contact withthe axis portion 2 and the flange portion 3.

Diffracted X-Rays Measurement Device

As shown in FIG. 2 , the diffracted X-rays measurement device 10includes an irradiation unit 11 which delivers X-rays; a two-dimensionaldetector 12 which detects a diffraction ring generated by Braggdiffraction of the X-rays delivered from the irradiation unit 11 to thefillet portion 4 (more specifically, a measurement site S in the filletportion 4); and a housing 13 in which the irradiation unit 11 and thetwo-dimensional detector 12 are mounted. The diffracted X-raysmeasurement device 10 is configured to be able to calculate a residualstress of the fillet portion 4 by the cos α method. Specifically, thediffracted X-rays measurement device 10 is configured to be able toirradiate the measurement site S with X-rays, to detect intensity ofdiffracted X-rays generated by reflection of the X-rays by thetwo-dimensional detector 12, and to calculate a residual stress on thebasis of a diffraction ring formed by an intensity distribution of thediffracted X-rays which have been detected. In addition, the diffractedX-rays measurement device 10 is configured to be able to calculate ahalf width of an X-ray diffraction intensity curve based on theintensity distribution of the diffracted X-rays. The “half width of anX-ray diffraction intensity curve” as referred to means a width of aprofile at an intensity value of half the peak of the X-ray diffractionintensity curve. The half width is reported to vary to reflectnon-uniform strain caused by quenching, tempering, plastic deformation,and the like, and considered to be in correlation to, for example,hardness, plastic strain, and the like of the fillet portion 4. The halfwidth may also be, for example, a value calculated for an arbitraryX-ray diffraction intensity curve constituting the diffraction ring, anaverage value of values calculated for a plurality of X-ray diffractionintensity curves constituting the diffraction ring, and the like.

The two-dimensional detector 12 is provided at an end on an X-rayemission side of the housing 13. That is to say, the two-dimensionaldetector 12 is provided at an end on a side facing a measurement site S.The two-dimensional detector 12 is exemplified by an imaging plate. Thehousing 13 has, for example, a substantially rectangular parallelepipedshape. The housing 13 has: the lower surface 13 a adjacent to the axisportion 2; and the upper surface 13 b facing the lower surface 13 a andbeing adjacent to the flange portion 3. The irradiation unit 11 and thetwo-dimensional detector 12 are integrally provided through beingarranged in the housing 13. A calculator 14 capable of using thediffraction ring to calculate the residual stress by the cos α method isconnected to the housing 13. In addition, the calculator 14 isconfigured to be able to calculate a half width of an X-ray diffractionintensity curve based on the intensity distribution of the diffractedX-rays.

Positioning Device

As shown in FIG. 3 , the positioning device 20 includes: a movingmechanism 21 that moves three-dimensionally the diffracted X-raysmeasurement device 10 relative to the fillet portion 4; and a rotationmechanism 22 that rotates the diffracted X-rays measurement device 10 insuch a direction that an angle of incidence Ψ (see FIG. 2 ) of theX-rays with respect to the fillet portion 4 is changed. The movingmechanism 21 is connected to the axis portion 2 or the flange portion 3.The moving mechanism 21 is connected to the axis portion 2 in thepresent embodiment.

Moving Mechanism

The moving mechanism 21 includes: a first moving body 23 that fits to anouter peripheral face of the axial portion 2 and rotates in acircumferential direction relative to the axial portion 2; aperpendicular axis 24 that is connected to the first moving body 23 andextends in a direction orthogonal to the central axis of the axisportion 2; a second moving body 25 that is connected to theperpendicular axis 24 and movable in an axial direction of theperpendicular axis 24; and a slide mechanism 26 that moves theperpendicular axis 24 in an axial direction of the axis portion 2. thediffracted X-rays measurement device 10 is connected to the secondmoving body 25.

As shown in FIG. 3 , the first moving body 23 includes: a frame 23 athat fits to the outer peripheral face of the axial portion 2; aplurality of rollers 23 c of which rotational axes 23 b are arranged inparallel to the central axis of the axis portion 2 and that are incontact with the outer peripheral face of the axial portion 2; and amotor 23 d that rotationally drives the plurality of rollers 23 c. Thefirst moving body 23 rotationally drives the plurality of rollers 23 cby the motor 23 d to rotate the diffracted X-rays measurement device 10in a circumferential direction relative to the axis portion 2. The firstmoving body 23 may also rotate the axis portion 2 in a circumferentialdirection to rotate the diffracted X-rays measurement device 10 in acircumferential direction relative to the axis portion 2. Alternatively,in the measurement system 1, the first moving body 23 may rotate in thecircumferential direction of the axis portion 2 to rotate the diffractedX-rays measurement device 10 in the circumferential direction relativeto the axis portion 2.

The perpendicular axis 24 may be either directly connected to the firstmoving body 23, or connected to the first moving body 23 via anothermember. In the present embodiment, the perpendicular axis 24 isconnected to the first moving body 23 via the slide mechanism 26.

The second moving body 25 is configured to fit to the perpendicular axis24 and to be movable in the axial direction of the perpendicular axis 24by a motor (not shown in the figure). The second moving body 25 is, forexample, in a frame-like shape externally fitting to the perpendicularaxis 24.

The slide mechanism 26 includes a supporting portion 26 a that supportsthe perpendicular axis 24 in a slidable manner in the axial direction ofthe axis portion 2, and a motor (not shown in the figure) that drivesthe perpendicular axis 24 in the axial direction of the axis portion 2.

In the measurement system 1, due to the moving mechanism 21 includingthe first moving body 23, the perpendicular axis 24, the second movingbody 25, and the slide mechanism 26, and the diffracted X-raysmeasurement device 10 being connected to the second moving body 25, themoving mechanism 21 is less likely to be hindered from arranging thediffracted X-rays measurement device 10 in a desired position. In otherwords, in a case of measuring the residual stress and the like of thefillet portion 4 by the diffracted X-rays measurement device 10,irradiation of the fillet portion 4 with X-rays in a desired arrangementmay be difficult due to interference between the diffracted X-raysmeasurement device 10 or the positioning device 20, and the axis portion2 or the flange portion 3. In this regard, due to the moving mechanism21 having the above-described configuration, the measurement system 1enables easy and reliable measurement of the residual stress and thelike of the fillet portion 4 in a desired arrangement, while inhibitinginterference between the diffracted X-rays measurement device 10 or thepositioning device 20, and the axis portion 2 or the flange portion 3.

Rotation Mechanism

The rotation mechanism 22 includes: a connecting body 22 a that connectsthe second moving body 25 and the diffracted X-rays measurement device10; and a motor (not shown in the figure) that rotationally drives theconnecting body 22 a around an axis perpendicular to the central axis ofthe axis portion 2. The diffracted X-rays measurement device 10 isdirectly connected to the connecting body 22 a, and connected to thesecond moving body 25 via the connecting body 22 a.

Control Unit

The control unit 30 is configured to include, for example, a computerwith: a CPU (Central Processing Unit) that carries out data processing;and a storage unit such as semiconductor memory that stores varioustypes of data transitorily or permanently. The control unit 30 controlsmovement by the moving mechanism 21 and rotation by the rotationmechanism 22 such that the diffracted X-rays measurement device 10 doesnot come in contact with the axis portion 2 and the flange portion 3.Due to including the control unit 30, the measurement system 1 caneasily measure the residual stress and the like of the fillet portion 4in a desired arrangement.

The control unit 30 controls the movement by the moving mechanism 21 andthe rotation by the rotation mechanism 22 within such a range that thediffracted X-rays measurement device 10 (more specifically, thetwo-dimensional detector 12) can detect a peak of diffracted X-rays.According to this configuration, the residual stress and the like of thefillet portion 4 can be measured easily and reliably.

A control procedure by the control unit 30 is described with referenceto FIG. 2 . The control unit 30 controls arrangement of the housing 13by using a two-dimensional Cartesian coordinate system in which acoordinate of the fillet center P is represented by (0, 0), an axispassing through the fillet center P and being parallel to the centralaxis of the axis portion 2 is represented by an X-axis, and an axispassing through the fillet center P and being parallel to a protrudingdirection of the flange portion 3 is represented by a Z-axis.

The control unit 30 controls the arrangement of the diffracted X-raysmeasurement device 10 such that, in a case in which: a coordinate of arotation center Q of the diffracted X-rays measurement device 10 isrepresented by (X, Z); an irradiation distance of the X-rays by thediffracted X-rays measurement device 10 is denoted by L [mm]; a minimumvalue of the irradiation distance L of the X-rays is denoted by L_(min)[mm]; a maximum value of the irradiation distance L of the X-rays isdenoted by L_(max) [mm]; a fillet angle is denoted by θ [°]; a filletradius is denoted by R [mm]; an angle of incidence of X-rays (an angleformed by an imaginary straight line N that passes through themeasurement site S and the fillet center P; and the X-rays) is denotedby Ψ [°]; a distance between an end portion of the housing 13 on thefillet portion 4 side and the rotation center Q in the irradiationdirection of the X-rays is denoted by h [mm]; a top-to-bottom width ofan end portion of the housing 13 on a side adjacent to the filletportion 4 (width between the lower surface 13 a and the upper surface 13b) is denoted by W [mm]; a complementary angle of the Bragg angle isdenoted by η [°]; a top-to-bottom width of the two-dimensional detector12 is denoted by D [mm]; and an interval between the flange portion 3and an imaginary straight line which passes through the fillet center Pand is parallel to the flange portion 3 is denoted by a [mm], thefollowing inequality 1 and inequality 2 are satisfied.

(L _(min) +h)cos(θ+ψ)−R cos θ≤X≤(L _(max) +h)sin(θ+Ψ)−R sin θ  1

(L _(min) +h)cos(θ+Ψ)−R cos θ≤Z≤(L _(max) +h)cos(θ+Ψ)−R cos θ  2

With respect to the imaginary straight line N which passes through themeasurement site S and the fillet center P, the angle of incidence Ψ ofthe X-rays is defined to be positive in a case of tilting toward theaxis portion 2, and is defined to be negative in a case of tiltingtoward the flange portion 3: in a case in which Ψ≥0, the irradiationdistance L of the X-rays satisfies the following inequality 3; and in acase in which Ψ<0, the irradiation distance L of the X-rays satisfiesthe following inequality 4.

$\begin{matrix}{\frac{{- {R\left( {1 - {\cos\theta}} \right)}} + {\frac{W}{2}{\sin\left( {\theta + \Psi} \right)}}}{\cos\left( {\theta + \Psi} \right)} \leqq L \leqq \frac{D}{2\tan\eta}} & 3\end{matrix}$ $\begin{matrix}{\frac{{R\sin\theta} + {\frac{W}{2}{\cos\left( {\theta + \Psi} \right)}} - a}{\sin\left( {\theta + \Psi} \right)} \leqq L \leqq \frac{D}{2\tan\eta}} & 4\end{matrix}$

Due to positioning the diffracted X-rays measurement device 10 within arange that satisfies the above formulae 1 and 2, the measurement system1 can easily inhibit contact of the axis portion 2 and the flangeportion 3 with the diffracted X-rays measurement device 10.

It is preferred that, in a case in which Ψ≥0, the control unit 30controls movement by the moving mechanism 21 and rotation by therotation mechanism 22 on the basis of the following inequality 5.

$\begin{matrix}{Z \geqq {{- R} + {h{\cos\left( {\theta + \Psi} \right)}} + {\frac{W}{2}{{\sin\left( {\theta + \Psi} \right)}.}}}} & 5\end{matrix}$

Meanwhile, it is preferred that, in a case in which Ψ<0, the controlunit 30 controls movement by the moving mechanism 21 and rotation by therotation mechanism 22 on the basis of the following inequality 6.

$\begin{matrix}{X \geqq {{- a} + {h{\sin\left( {\theta + \Psi} \right)}} + {\frac{W}{2}{{\cos\left( {\theta + \Psi} \right)}.}}}} & 6\end{matrix}$

Due to thus controlling the movement by the moving mechanism 21 and therotation by the rotation mechanism 22 on the basis of the above formulae5 and 6, the measurement system 1 can measure the residual stress andthe like of the fillet portion 4 easily and reliably, while contact ofthe axis portion 2 and the flange portion 3 with the diffracted X-raysmeasurement device 10 is inhibited.

FIG. 4 shows a relationship between the angle of incidence Ψ of theX-rays and the measurement error in the residual stress. As shown inFIG. 4 , when the absolute value of the angle of incidence Ψ of theX-rays is smaller, an impact of a configuration error in the angle ofincidence of the X-rays is greater. Particularly when the absolute valueof the angle of incidence Ψ of the X-rays is less than 10°, an impact ofthe configuration error in the angle of incidence of the X-rays isremarkable. Therefore, it is preferred that the control unit 30 controlsthe arrangement of the housing 13 such that the absolute value of theangle of incidence Ψ of the X-rays is at least 10°, and preferably atleast 20°.

In the measurement system 1, due to the control unit 30 that controlsthe movement mechanism 21 and the rotation mechanism 22, the housing 13can be easily arranged so as to increase the absolute value of the angleof incidence Ψ of the X-rays. In other words, in a case of arranging thehousing 13 manually, it is not easy to find an arrangement in which theabsolute value of the angle of incidence Ψ of the X-rays is great insuch a range that the housing 13 does not come into contact with theaxis portion 2 and the flange portion 3. On the other hand, in themeasurement system 1, due to the control unit 30 that controls themovement mechanism 21 and the rotation mechanism 22, the desiredarrangement of the housing 13 can be automatically found, and thehousing 13 can be moved and rotated to be in this arrangement.

It is preferred that, with respect to the fillet angle θ of the filletportion 4, the control unit 30 derives such an irradiation distance L ofthe X-rays and such an angle of incidence Ψ of the X-rays that thediffracted X-rays measurement device 10 does not come into contact withthe axis portion 2 and the flange portion 3. Specifically, the controlunit 30 accepts, with respect to the particular fillet angle θ, inputsof the irradiation distance L of the X-rays and the angle of incidence Ψof the X-rays desired by a user. When the irradiation distance L of theX-rays and the angle of incidence Ψ of the X-rays are input, the controlunit 30 determines whether it is possible to arrange the housing 13 withthe irradiation distance L of the X-rays and the angle of incidence Ψ ofthe X-rays being input by the user, on the basis of the above inequality5 or 6. In a case in which it is possible to arrange the housing 13 withthe irradiation distance L of the X-rays and the angle of incidence Ψ ofthe X-rays being input by the user, the control unit 30 moves androtates the housing 13 in the arrangement corresponding to the inputvalues, or notifies the user that the arrangement of the housing 13 ispossible. According to this configuration, the residual stress and thelike of the fillet portion 4 can be measured more easily in the desiredarrangement.

It is preferred that the control unit 30 derives the irradiationdistance L of the X-rays and the angle of incidence Ψ of the X-rays withwhich arrangement of the housing 13 is possible, for a plurality offillet angles θ. In the measurement system 1, due to the control unit 30that controls the movement mechanism 21 and the rotation mechanism 22,the residual stress of the fillet portion 4 can be calculated for aplurality of times in a desired arrangement and in a short period oftime.

Note that, in a case of calculating the half width of the X-raydiffraction intensity curve, the diffracted X-rays measurement device 10is not required to be arranged to increase the absolute value of theangle of incidence Ψ of the X-rays. For example, in a case ofcalculating the half width of the X-ray diffraction intensity curve, theangle of incidence Ψ of the X-rays may be 0°. However, in themeasurement system 1, an arrangement of the diffracted X-raysmeasurement device 10 suited for calculating the residual stress of thefillet portion 4 facilitates calculation of both the residual stress ofthe fillet portion 4 and the half width of the X-ray diffractionintensity curve.

It is preferred that the control unit 30 controls the movement by themoving mechanism 21 and the rotation by the rotation mechanism 22 suchthat the diffracted X-rays measurement device 10 is rotated in thecircumferential direction of the axis portion 2, or moved in aparticular plane including the central axis of the axis portion 2.

The diffracted X-rays measurement device 10 may either deliver theX-rays continuously in parallel to positioning by the positioning device20, or deliver the X-rays after positioning in a particular arrangementby the positioning device 20. Specific examples of the diffracted X-raysmeasurement device 10 delivering the X-rays continuously in parallel topositioning by the positioning device 20 include a configuration ofdelivering the X-rays while the diffracted X-rays measurement device 10is relatively rotated in the circumferential direction of the axisportion 2. According to this configuration, the residual stress and thelike of the fillet portion 4 can be measured easily and with highaccuracy.

In a case in which the diffracted X-rays measurement device 10 hascalculated the residual stress of the fillet portion 4 for a pluralityof times, it is preferred that the diffracted X-rays measurement device10 determines an average value of a plurality of calculated values(calculated values of the residual stress) by the calculator 14.Alternatively, in a case in which the diffracted X-rays measurementdevice 10 has calculated the half width of the X-ray diffractionintensity curve for a plurality of times, it is preferred that thediffracted X-rays measurement device 10 determines an average value of aplurality of calculated values (calculated values of the half width) bythe calculator 14. Due to determining the average value of the pluralityof calculated values by the calculator 14, the measurement system 1 canreduce the measurement error in the residual stress or the half width.

FIG. 5 shows a relationship between the irradiation area of the X-raysand the measurement error in the residual stress. In FIG. 5 , acollimated diameter of letting through the X-rays is 1 mm, and anirradiation area of one point is about 6.5 mm². As shown in FIG. 5 ,increasing a total value of the irradiation area enables reduction inthe measurement error in the residual stress. Particularly, the totalvalue of the irradiation area being at least 25 mm² enables sufficientreduction in the measurement error in the residual stress. A method forincreasing the total value of the irradiation area of the X-rays isexemplified by a method of delivering the X-rays for a plurality oftimes while arbitrarily changing the arrangement of the housing 13, amethod of delivering the X-rays while swinging the housing 13 in thecircumferential direction of the axis portion 2, a method of deliveringthe X-rays at a plurality of angles of incidence Ψ, and the like. Notethat in FIG. 5 , with regard to a segregation portion of a bainiticstructure, a portion with no segregation of the bainitic structure, anda martensite structure, the X-rays are delivered for a plurality oftimes such that the respective total values of the irradiation areas aregreat.

Measuring Method

Next, the measurement method according to an embodiment of the presentinvention is described. The measurement method measures an intensitydistribution of diffracted X-rays obtained by irradiating with X-rays afillet portion 4 of a metallic structure M, the metallic structure Mincluding: an axis portion 2; and a flange portion 3 protruding radiallyfrom the axis portion 2, in which the metallic structure M includes thefillet portion 4 in a connection portion between the axis portion 2 andthe flange portion 3. The measurement method can be carried out by usingthe measurement system 1 illustrated in FIG. 1 . Therefore, themeasurement method using the measurement system 1 is describedhereinafter.

The measurement method includes a step (moving step) of movingthree-dimensionally the diffracted X-rays measurement device 10 relativeto the fillet portion 4; a step (rotating step) of rotating thediffracted X-rays measurement device 10 in such a direction that anangle of incidence Ψ of the X-rays with respect to the fillet portion 4is changed; and a step (measuring step) of measuring the intensitydistribution of diffracted X-rays by the diffracted X-rays measurementdevice 10. The measurement method may include, after the measuring step,a step (repeating step) of repeating: at least one of the moving stepand the rotating step; and the measuring step. The measurement methodmay also include a step (average value calculating step) of determiningan average value of a plurality of calculated values determined by themeasuring step (a plurality of calculated values of the residual stressor a plurality of calculated values of the half width).

Moving Step

In the moving step, the housing 13 is moved to a desired position by thecontrol unit 30 that controls the moving mechanism 21.

Rotating Step

In the rotating step, the housing 13 is rotated to a desired angle bythe control unit 30 rotating the rotation mechanism 22. Note that themoving step and the rotating step may take place either one afteranother or simultaneously.

Measuring Step

In the measuring step, the residual stress of the fillet portion 4 iscalculated by the cos α method. Specifically, in the measuring step, theresidual stress is calculated on the basis of a diffraction ringgenerated by Bragg diffraction of the X-rays delivered from thediffracted X-rays measurement device 10 to the fillet portion 4 (morespecifically, the measurement site S). In addition, in the measuringstep, the half width of the X-ray diffraction intensity curve based onthe intensity distribution of the diffracted X-rays is calculated.

The measuring step may be configured to, for example, irradiate thefillet portion 4 with X-rays in the arrangement after the moving stepand the rotating step, detect by the two-dimensional detector 12 thediffraction ring generated by Bragg diffraction of the X-rays delivered,and calculate the residual stress by the calculator 14 using the cos αmethod. Alternatively, the measuring step may be configured to irradiatethe fillet portion 4 with X-rays in the arrangement after the movingstep and the rotating step, and calculate the half width of the X-raydiffraction intensity curve.

Yet alternatively, the measuring step may be configured to continuouslyirradiate the fillet portion with X-rays in parallel with at least oneof the moving step and the rotating step, and obtain a singlediffraction ring, which is given by overlapping a plurality ofdiffraction rings generated by diffraction of the X-rays. In this case,in the measuring step, the residual stress may be calculated on thebasis of the single diffraction ring thus obtained. More specifically,it may be configured that the diffracted X-rays measurement device 10constantly delivers X-rays to a continuously connected portion of thefillet portion 4 in parallel to at least one of the moving step and therotating step, the two-dimensional detector 12 detects a singlediffraction ring, which is given by overlapping a plurality ofdiffraction rings generated by diffraction of each of the X-rays at thefillet portion 4, and the residual stress is calculated on the basis ofthe single diffraction ring in the measuring step. A configuration ofcontinuously delivering X-rays to the fillet portion 4 in parallel to atleast one of the moving step and the rotating step is exemplified by amethod of continuously delivering X-rays to the fillet portion 4 whilerelatively rotating the diffracted X-rays measurement device 10 in thecircumferential direction of the axis portion 2. Due to calculating theresidual stress on the basis of the single diffraction ring in themeasuring step, the measurement method enables easily measuring, withhigh accuracy, the residual stress of the fillet portion 4.Alternatively, the measuring method may be configured to calculate thehalf width on the basis of the single diffraction ring (in other words,on the basis of the X-ray diffraction intensity curve obtained bycontinuously delivering X-rays to the fillet portion 4 in parallel to atleast one of the moving step and the rotating step). Note that, in acase of calculating the residual stress and the like on the basis of thesingle diffraction ring in the measuring step, the measurement method isnot required to include the repeating step and the average valuecalculating step described later.

Repeating Step

In the repeating step, the arrangement of the housing 13 with respect tothe fillet portion 4 is changed by carrying out at least one of themoving step and the rotating step after the measuring step. In therepeating step, the residual stress of the fillet portion 4 iscalculated by delivering the X-rays from the diffracted X-raysmeasurement device 10 in the arrangement thus changed. Since theresidual stress of the fillet portion 4 is typically distributed in acertain manner, carrying out the repeating step facilitatescomprehension of the distribution of the residual stress. In addition,in the repeating step, the half width of the X-ray diffraction intensitycurve is calculated by delivering X-rays from the diffracted X-raysmeasurement device 10 in the changed arrangement. Since the half widthof the X-ray diffraction intensity curve may vary depending on theirradiation position of the X-rays, the repeating step facilitates moreaccurate comprehension of the half width.

The number of repetitions by the repeating step is arbitrary, and may beone. However, as shown in FIG. 5 , in light of sufficiently reducing themeasurement error in the residual stress, the repeating step ispreferably carried out repeatedly until the total value of theirradiation area of the X-rays is at least 25 mm². In the repeatingstep, the residual stress may be calculated at a plurality of angles ofincidence Ψ while changing the angle of incidence Ψ of the X-rays withrespect to one measurement site S. For example, in the repeating step,the residual stress may be calculated at a plurality of angles ofincidence Ψ while changing the angle of incidence Ψ of the X-rays by10°.

Average Value Calculating Step

In the average value calculating step, an average value of valuescalculated by the measuring step carried out for a plurality of timesincluding those of the repeating step. In the measurement method, theaverage value (average value of the residual stress) is calculated asthe residual stress of the fillet portion 4. In addition, in themeasurement method, the average value (average value of the half width)is calculated as the half width of the X-ray diffraction intensitycurve. Due to including the average value calculating step, themeasurement method enables easy measurement of the residual stress andthe half width with reduced measurement errors.

Advantages

The measurement system 1 includes the positioning device 20 thatpositions the diffracted X-rays measurement device 10 with respect tothe fillet portion 4, the positioning device 20 including: the movingmechanism 21 that moves three-dimensionally the diffracted X-raysmeasurement device 10 relative to the fillet portion 4; and the rotationmechanism 22 that rotates the diffracted X-rays measurement device 10 insuch a direction that the angle of incidence Ψ of the X-rays withrespect to the fillet portion 4 is changed, whereby an intensitydistribution of diffracted X-rays obtained by irradiating the filletportion 4 with X-rays can be easily measured in a desired arrangement.

The measurement system 1 being able to easily measure the intensitydistribution of the diffracted X-rays in a desired arrangement is suitedfor calculating the residual stress of the fillet portion 4. In otherwords, the fillet portion 4 typically has a distribution of the residualstress in a direction of change of the angle of incidence Ψ of theX-rays, the circumferential direction of the axis portion 2, and thelike. The measurement system 1 enables positioning of the diffractedX-rays measurement device 10 with high accuracy in a short period oftime, thus facilitating measurement of the residual stress in aplurality of positions in the fillet portion 4. As a result, thedistribution of the residual stress of the fillet portion 4 can beeasily comprehended.

In addition, the measurement system 1 being able to easily measure theintensity distribution of the diffracted X-rays in a desired arrangementis suited for calculating the half width of the X-ray diffractionintensity curve.

Due to the measurement method including a step of movingthree-dimensionally the diffracted X-rays measurement device 10 relativeto the fillet portion 4; and a step of rotating the diffracted X-raysmeasurement device 10 in such a direction that an angle of incidence Ψof the X-rays with respect to the fillet portion 4 is changed, anintensity distribution of diffracted X-rays obtained by irradiating thefillet portion 4 with X-rays can be easily measured in a desiredarrangement.

The measurement method being able to easily measure the intensitydistribution of the diffracted X-rays in a desired arrangement is suitedfor calculating the residual stress of the fillet portion 4. Inaddition, the measurement method being able to easily measure theintensity distribution of the diffracted X-rays in a desired arrangementis suited for calculating the half width of the X-ray diffractionintensity curve.

Other Embodiments

The above-described embodiments do not limit the configuration of thepresent invention. Therefore, in the above-described embodiments, thecomponents of each part of the above-described embodiments can beomitted, replaced, or added based on the description in the presentspecification and general technical knowledge, and such omission,replacement, or addition should be construed as falling within the scopeof the present invention.

The configuration of the positioning device is not limited to theconfiguration of the above-described embodiments. For example, in thepositioning device, the moving mechanism may be connected to the flangeportion. With reference to FIG. 6 , an example of the configuration inwhich the moving mechanism is connected to the flange portion isdescribed. In the positioning device 40 illustrated in FIG. 6 , a movingmechanism 41 is connected to an upper face of the flange portion 3. Themoving mechanism 41 includes: a support base 41 a that is arranged onthe upper face of the flange portion 3; a first supporting rod 41 b thatprotrudes upward from the support base 41 a and is rotatable in acircumferential direction; a second supporting rod 41 c that isconnected to the first supporting rod 41 b and extends in a directionorthogonal to the first supporting rod 41 b; a moving body 41 d that isconnected to the second supporting rod 41 c and movable in an axialdirection of the second supporting rod 41 c; and a third supporting rod41 e that is connected to the moving body 41 d, arranged in parallel tothe first supporting rod 41 b, and movable in a top-to-bottom direction.The diffracted X-rays measurement device 10 is connected to a lowerportion of the third supporting rod 41 e via the rotation mechanism 42.In the configuration of FIG. 6 as well, the measurement system enablesmeasurement of the residual stress and the like of the fillet portion 4in a desired arrangement.

In the above-described embodiments, the configuration in which the slidemechanism moves the perpendicular axis in the axial direction of theaxis portion has been described. However, the measurement system mayalso be configured such that the slide mechanism moves the first movingbody in the axial direction of the axis portion.

The measurement system may also be configured not to include theabove-described control unit. For example, the measurement system mayalso be configured to arrange the diffracted X-rays measurement devicein a desired position by means of the moving mechanism and the rotationmechanism operated by a user. In addition, even in a case in which themeasurement system includes the control unit, the specific controlprocedure by the control unit is not limited to the configuration of theabove-described embodiments. For example, the control unit may controlthe moving mechanism and the rotation mechanism to arrange thediffracted X-rays measurement device such that the angle of incidence Ψof the X-rays approaches ±35° with respect to a particular fillet angle.

The measurement system and the measurement method may also be configuredto enable calculation of only one of the residual stress of the filletportion and the half width of the X-ray diffraction intensity curve.Alternatively, the measurement system and the measurement method mayalso be configured to calculate a value other than the residual stressof the fillet portion and the half width of the X-ray diffractionintensity curve.

As described above, in light of reducing the measurement error, it ispreferred that the measurement method calculates the residual stress andthe like of the fillet portion in a plurality of arrangements. However,in a case in which the absolute value of the angle of incidence Ψ of theX-rays can be sufficiently increased or the like, the measurement methodmay determine the residual stress and the like of the fillet portionfrom a value of only one desired point. In such a case, the measurementmethod is not required to include the repeating step and the averagevalue calculating step described above.

Examples

Hereinafter, the present invention is described in detail by way ofExamples, but the present invention should not be construed as beinglimited to description in the Examples.

By the measurement system 1 of FIG. 1 , the residual stress of thefillet portion 4 of the metallic structure M including the axis portion2 and the flange portion 3 protruding radially from the axis portion 2was measured by the cos α method. As the diffracted X-rays measurementdevice 10, an X-ray stress measuring apparatus was used in which atop-to-bottom width D of the detection region of the two-dimensionaldetector 12 was 70 mm, and a top-to-bottom width of the housing 13 was102 mm. The fillet radius R of the fillet portion 4 was 29 mm, thecomplementary angle η of the Bragg angle was 23.6°, and the interval abetween the flange portion 3 and the imaginary straight line whichpasses through the fillet center P and is parallel to the flange portion3 was 8 mm.

FIG. 7 shows measurement results of the residual stress using themeasurement system 1. In FIG. 7 , with respect to a plurality of filletangles θ, the control unit 30 derives such an irradiation distance L ofthe X-rays and such an angle of incidence Ψ of the X-rays that thediffracted X-rays measurement device 10 does not come into contact withthe axis portion 2 and the flange portion 3, and the residual stress ofthe fillet portion 4 is measured in the arrangement thus derived. Asshown in FIG. 7 , due to using the measurement system 1, the residualstress can be automatically measured for a plurality of fillet angles θ.

FIG. 8 shows a relationship between the number of measured points andthe measuring time in a case of using the measurement system 1 (Example)and in a case of arranging the housing manually without using themeasurement system 1 (Comparative Example). As shown in FIG. 8 , whenthe number of measured points is greater, using the measurement system 1enables greater reduction of the measuring time.

In addition, FIG. 9 shows the half width calculated from the X-raydiffraction intensity curve obtained with the arrangement derived by themeasurement in FIG. 7 . In FIG. 9 , an error bar indicates a rangebetween the maximum value and the minimum value of the half width of theX-ray diffraction intensity curve constituting the diffraction ring, andeach dot indicates an average value of the half width. FIG. 9 indicatesthat the measurement system 1 enables calculation of the half width ofthe X-ray diffraction intensity curve.

INDUSTRIAL APPLICABILITY

As described above, the measurement system according to the one aspectof the present invention is suited for measuring the residual stress andthe like of the fillet portion.

EXPLANATION OF THE REFERENCE SYMBOLS

-   -   1 Measurement system    -   2 Axis portion    -   3 Flange portion    -   4 Fillet portion    -   10 Diffracted X-rays measurement device    -   11 Irradiation unit    -   12 Two-dimensional detector    -   13 Housing    -   13 a Lower surface    -   13 b Upper surface    -   14 Calculator    -   20, 40 Positioning device    -   21, 41 Moving mechanism    -   22, 42 Rotation mechanism    -   22 a Connecting body    -   23 First moving body    -   23 a Frame    -   23 b Rotational axis    -   23 c Roller    -   23 d Motor    -   24 Perpendicular axis    -   25 Second moving body    -   26 Slide mechanism    -   26 a Supporting portion    -   30 Control unit    -   41 a Supporting base    -   41 b First supporting rod    -   41 c Second supporting rod    -   41 d Moving body    -   41 e Third supporting rod    -   a Interval between flange portion and imaginary straight line        which passes through fillet center and is parallel to flange        portion    -   D Top-to-bottom width of detection region of two-dimensional        detector    -   h Distance between end portion of housing on fillet portion side        and rotation center in irradiation direction of X-rays    -   L Irradiation distance of X-rays    -   M Metallic structure    -   N Imaginary straight line which passes through measurement site        and fillet center    -   P Fillet center    -   Q Rotation center of diffracted X-rays measurement device    -   R Fillet radius    -   S Measurement site    -   W Top-to-bottom width of end portion of housing on side adjacent        to fillet portion    -   θ Fillet angle    -   Ψ Angle of incidence of X-rays    -   η Complementary angle of Bragg angle

1. A measurement system enabling measurement of an intensitydistribution of diffracted X-rays obtained by irradiating a filletportion of a metallic structure with X-rays, the metallic structurecomprising: an axis portion; and a flange portion protruding radiallyfrom the axis portion, wherein the metallic structure comprises thefillet portion in a connection portion between the axis portion and theflange portion, the measurement system comprising: a diffracted X-raysmeasurement device provided with an irradiation unit that irradiates thefillet portion with X-rays; and a positioning device that positions thediffracted X-rays measurement device with respect to the fillet portion,wherein the positioning device comprises: a moving mechanism that movesthree-dimensionally the diffracted X-rays measurement device relative tothe fillet portion; and a rotation mechanism that rotates the diffractedX-rays measurement device in such a direction that an angle of incidenceof the X-rays with respect to the fillet portion is changed.
 2. Themeasurement system according to claim 1, further comprising a controlunit that controls movement by the moving mechanism and rotation by therotation mechanism such that the diffracted X-rays measurement devicedoes not come into contact with the axis portion and the flange portion.3. The measurement system according to claim 2, wherein the control unitcontrols the movement by the moving mechanism and the rotation by therotation mechanism within such a range that the diffracted X-raysmeasurement device can detect a peak of diffracted X-rays.
 4. Themeasurement system according to claim 3, wherein, in a case in which: anaxis passing through a fillet center and being parallel to a centralaxis of the axis portion is represented by an X-axis; an axis passingthrough the fillet center and being parallel to a protrusion directionof the flange portion is represented by a Z-axis; a coordinate of thefillet center is represented by (0, 0); a coordinate of a rotationcenter of the diffracted X-rays measurement device is represented by (X,Z); an irradiation distance of the X-rays by the diffracted X-raysmeasurement device is denoted by L [mm]; a minimum value of theirradiation distance of the X-rays is denoted by L_(min) [mm]; a maximumvalue of the irradiation distance of the X-rays is denoted by L_(max)[mm]; a fillet angle is denoted by θ [°]; a fillet radius is denoted byR [mm]; an angle of incidence of the X-rays is denoted by Ψ [°]; adistance between an end portion of a housing of the diffracted X-raysmeasurement device on the fillet portion side and the rotation center inthe irradiation direction of the X-rays is denoted by h [mm]; atop-to-bottom width of an end portion of the housing on a side adjacentto the fillet portion is denoted by W [mm]; a complementary angle of theBragg angle is denoted by η [°]; a top-to-bottom width of a detectionregion of a two-dimensional detector of the diffracted X-raysmeasurement device is denoted by D [mm]; and an interval between theflange portion and an imaginary straight line which passes through thefillet center and is parallel to the flange portion is denoted by a[mm], inequality 1 and inequality 2 are satisfied:(L _(min) +h)sin(θ+Ψ)−R sin θ≤X≤(L _(max) +h)sin(θ+Ψ)−R sin θ  1(L _(min) +h)cos(θ+Ψ)−R cos θ≤Z≤(L _(max) +h)cos(θ+Ψ)−R cos θ  2 whereinwith respect to an imaginary straight line which passes through ameasurement site and the fillet center, the angle of incidence Ψ of theX-rays is defined to be positive in a case of tilting toward the axisportion, and is defined to be negative in a case of tilting toward theflange portion: in a case in which Ψ≥0, the irradiation distance L ofthe X-rays satisfies inequality 3; and in a case in which Ψ<0, theirradiation distance L of the X-rays satisfies inequality 4:$\begin{matrix}{\frac{{- {R\left( {1 - {\cos\theta}} \right)}} + {\frac{W}{2}{\sin\left( {\theta + \Psi} \right)}}}{\cos\left( {\theta + \Psi} \right)} \leqq L \leqq \frac{D}{2\tan\eta}} & 3\end{matrix}$ $\begin{matrix}{\frac{{R\sin\theta} + {\frac{W}{2}{\cos\left( {\theta + \Psi} \right)}} - a}{\sin\left( {\theta + \Psi} \right)} \leqq L \leqq {\frac{D}{2\tan\eta}.}} & 4\end{matrix}$
 5. The measurement system according to claim 4, whereinthe control unit controls the movement by the moving mechanism and therotation by the rotation mechanism on basis of inequality 5 in a case inwhich Ψ≥0, and controls the movement by the moving mechanism and therotation by the rotation mechanism on basis of inequality 6 in a case inwhich Ψ<0, $\begin{matrix}{Z \geqq {{- R} + {h{\cos\left( {\theta + \Psi} \right)}} + {\frac{W}{2}{\sin\left( {\theta + \Psi} \right)}}}} & 5\end{matrix}$ $\begin{matrix}{X \geqq {{- a} + {h{\sin\left( {\theta + \Psi} \right)}} + {\frac{W}{2}{{\cos\left( {\theta + \Psi} \right)}.}}}} & 6\end{matrix}$
 6. The measurement system according to claim 1, whereinthe moving mechanism comprises: a first moving body that fits to anouter peripheral face of the axial portion and rotates in acircumferential direction relative to the axial portion; a perpendicularaxis that is connected to the first moving body and extends in adirection orthogonal to the central axis of the axis portion; a secondmoving body that is connected to the perpendicular axis and movable inan axial direction of the perpendicular axis; and a slide mechanism thatmoves the first moving body or the perpendicular axis in an axialdirection of the axis portion, wherein the diffracted X-rays measurementdevice is connected to the second moving body.
 7. The measurement systemaccording to claim 1, wherein the diffracted X-rays measurement deviceis configured to be able to calculate a residual stress of the filletportion by the cos α method.
 8. The measurement system according toclaim 1, wherein the diffracted X-rays measurement device is configuredto be able to calculate a half width of an X-ray diffraction intensitycurve.
 9. A measurement method enabling measurement of an intensitydistribution of diffracted X-rays obtained by irradiating a filletportion of a metallic structure with X-rays, the metallic structurecomprising: an axis portion; and a flange portion protruding radiallyfrom the axis portion, wherein the metallic structure comprises thefillet portion in a connection portion between the axis portion and theflange portion, the measurement method using a diffracted X-raysmeasurement device provided with an irradiation unit that irradiates thefillet portion with X-rays, and comprising: moving three-dimensionallythe diffracted X-rays measurement device relative to the fillet portion;rotating the diffracted X-rays measurement device in such a directionthat an angle of incidence of the X-rays with respect to the filletportion is changed; and measuring the intensity distribution ofdiffracted X-rays by the diffracted X-rays measurement device.
 10. Themeasurement method according to claim 9, wherein, in the measurement,the residual stress of the fillet portion is calculated by the cos αmethod.
 11. The measurement method according to claim 9, wherein, in themeasurement, a half width of an X-ray diffraction intensity curve iscalculated.
 12. The measurement method according to claim 10, wherein:the fillet portion is continuously irradiated with X-rays in parallelwith at least one of the moving and the rotating; and in themeasurement, a single diffraction ring, which is given by overlapping aplurality of diffraction rings generated by diffraction of the X-rays,is determined.
 13. The measurement method according to claim 10comprising, after the measuring, repeating: at least one of the movingand the rotating, and the measuring.
 14. The measurement methodaccording to claim 13, further comprising determining an average valueof a plurality of calculated values obtained by the measuring.